The present invention comprises a new and distinct cultivar of a birch tree, botanically known as Betula papyrifera, and is hereto referred to by the cultivar name xe2x80x9cOencixe2x80x9d.
xe2x80x98Oencixe2x80x99 was discovered by the inventor in a group Betula papyrifera in test plots of Evergreen Nursery Company, Inc. in New Carlise, Ohio, in 1986. xe2x80x98Oencixe2x80x99 was originated from the open pollinated cross in a birch selection/breeding program in Wooster, Ohio. The non-patented female parent was Betula papyrifera. The pollen parent was Betula papyrifera. xe2x80x98Oencixe2x80x99 was first noticed with broad, dense pyramidal growth habit, white exfoliating bark and a very high resistance to the Bronze Birch Borer. The growth habit renders it ideal for clumping. The first act of asexual reproduction of xe2x80x98Oencixe2x80x99 was accomplished by cuttings by the inventor from the initial selection in our test plot in New Carlisle, Ohio. Currently, asexual reproduction is accomplished by micropropagation or tissue culture in Olympia, Wash. Horticultural examination of selected units has demonstrated that the combination of characteristics as herein disclosed for xe2x80x98Oencixe2x80x99 are firmly fixed and retained through its successive generations of asexual reproduction. xe2x80x98Oencixe2x80x99 has been observed in Sturgeon Bay, Wis., and New Carlisle, Ohio, since 1986 and characteristics have been stably maintained. The cultivar reproduces true to type. The new cultivar has not been observed under all possible environmental conditions. The phenotype may vary somewhat with variations in environment such as temperature, day length and light intensity, without a change in the genotype of a cultivar. The following observations, measurements, and comparisons describe the plants grown in New Carlisle, Ohio, and Sturgeon Bay, Wis. under natural field conditions which approximate those generally used in commercial operations.
The following traits have been repeatedly observed and are determined to be basic characteristics of xe2x80x98Oencixe2x80x99 which in combination distinguish this birch tree as a new and distinct cultivar:
1. Distinctive broad, dense pyramidal growth habit with branching angles about 33-35xc2x0.
2. Bark color changes as the tree matures; from mahogany reddish brown turning to white.
3. Exfoliating bark when mature.
4. Very high resistance to the Bronze Birch Borer.
5. Moderate growth rate.
6. Drought tolerant.
The novel cultivar xe2x80x98Oencixe2x80x99 can be compared with the nonpatented Batula papyrifera. The foregoing characteristics are distinctive from the nonpatented variety because the nonpatented variety has a loose oval growth habit, a brown bark that turns white at maturity, variable resistance to Bronze Birch Borer and is not drought tolerant.